European patent publication 0 252 261, for example, discloses a rotary nozzle for a high pressure cleaning apparatus which comprises a nozzle housing in which a rotor body is journaled for rotation about an axis of the housing, i.e. is axially rotatable, and is set in rotation by the cleaning liquid flowing through the nozzle housing. Downstream of the rotary body or rotor, a nozzle is provided whose ends turned toward the outlet orifice of the nozzle housing is supported in a pocket bearing on the nozzle housing and has a discharge axis including an acute angle with the rotation axis of the rotor, whereby the discharged jet has a conical configuration surrounding the rotation axis as the rotor is propelled within the housing.
This rotor nozzle assembly has a rotor formed with a cup serving as an entrainer for the rotor and in which the nozzle itself extends at its end remote from the end engaging the pocket bearing. This system has the drawback that, should replacement of the rotor body or of the nozzle be necessary or desirable as a consequence of wear or for substitution of another nozzle or rotor body matched to particular applications of the apparatus, such replacement or exchange is rendered difficult by the manner in which the rotor body is mounted. For example, replacement requires that the nozzle end be fitted into the entrainer cup.
Furthermore, with this construction, sealing elements and bearing locations must be provided at the driving side of the rotor body. Such elements are highly sensitive to contaminants in the cleaning liquid and are thus subject to early failure.
Moreover, adjustment of the speed or the setting of the speed is not normally possible and the maximum angle of the spray cone is greatly limited.
Finally, since the inlet side of the nozzle is surrounded by free space, the cleaning liquid tends to become turbulent in this region and the flow through the nozzle tends to become highly turbulent, creating problems in the effect of delivery of the liquid.